About these values
In these tables are Pokémon with it different movesets. Click on "show more" to see the full table. If you want to check how good your Pokémon's moveset is use our form at the top of the site. We originally got our data from Professor_Kukui's Species Data table (here), but because he didnt updated it for generation 2 we copied his spreadsheet and now we update it ourselves (here). He used the terms "Dueling Ability" , "Gym Offense" and "Gym Defense". You can find the details on his table. But we will give you a short overview here.
Dueling Ability (Offense)
Dueling Ability is a reasonable measure if you don't often/ever dodge, as then you can only attack for as long as you can stay positive on HP. It is calculated by tankiness and gym offense. Tankiness is base HP multiplied by base defense and gym offense is explained below.
Gym Offense takes the better of No Weave/Weave Damage over 100s and multiplies by the Pokémon's base attack to arrive at a ranking of raw damage output. "Weave Damage" is determined by figuring out the total Power achieved over 100 seconds by using basic attack enough to charge up enough energy to do a charge attack, and then using charge attack as soon as possible to not waste energy. "No Weave Damage" is determined by figuring out the total Power achieved by doing nothing but spamming the basic attack over 100 seconds. For some movesets this will the better way to attack.
Gym Defense takes the calculated Gym Weave Damage over 100s and multiplies by Tankiness to arrive at a ranking of how much damage a Pokémon will output when defending a gym. "Gym Weave Damage" is an approximation of damage output while defending a gym determined by taking into account the fact that gym defenders wait 2 seconds before initiating any attack after the first two.